Most people will be familiar with asthma, even if they don’t have the condition themselves. They’ve likely seen an asthmatic using their inhaler at some point, and know that the primary characteristic of the condition is having difficulty breathing. So what is allergic asthma? Allergic asthma involves that same difficulty breathing due to a constricted airway and mucus buildup, but the reason it’s called allergic asthma is because the inflammation response that tightens the airway is due to an allergic reaction activating the body’s immune system. That’s different from a standard asthma attack, which doesn’t involve an immune system response and is instead triggered by genetic and environmental factors.
Allergic asthma can be defined as experiencing asthma symptoms – shortness of breath, wheezing, rapid and shallow breathing, body fatigue and weakness – due to exposure to an allergen. The most common allergens are pollen (seasonal allergies), dust, and mold. Allergic asthma can also have the individual experiencing standard allergy symptoms like itchy, watery eyes and constant sneezing that go along with breathing difficulties.
Allergic asthma is especially common in children, with 90% of children experiencing asthma having allergic asthma.
Again, allergic asthma is different from asthma because the person must be exposed to an allergen trigger in order for the immune system to be activated. Researchers have determined that over 100 different genes may be associated with this condition, but certain ones will only factor in for certain people.
There is also evidence that part of what causes this condition is an unbalanced immune system. A balanced immune system will have a relatively equal number of type 1 (Th1) or type 2 (Th2) immune reactions. People with allergic asthma have a disproportionately large number of type 2 reactions. The significance of this is that type 2 reactions promote the production of immune proteins called IgE antibodies.
These antibodies are responsible for affecting the muscles around the airway, constricting them and leading to allergic asthma symptoms. So it is not only the trigger itself that causes it, it is also that the excessive number of type 2 immune reactions has meant that there is an abundance of IgE antibodies being sent out by the immune system every time a trigger is received.
You’ll still need the trigger though. The most common allergen causes of this condition include:
Irritants can also be the cause of this condition, and the most common of these are:
For some people, allergic asthma is one progression in a series of allergic disorders experienced by the individual. This is called atopic march, and it involves developing a series of allergic disorders that follow a pattern. Typically this means developed eczema first, then food allergies, hay fever (seasonal pollen allergy) and then asthma.
The first step for treating people with this condition will be give them a peak expiratory flow test to monitor the extent to which the breathing capacity is inhibited by the condition. The person’s physician will then usually make recommendation for medications and preventative approaches. Standard inhaler medications for allergic asthma include:
Anticholinergic medications like Atrovent may be used in combination with SABA drugs to further bronchodilation in patients, and Cromolyn Sodium and Nedocromil are helpful for some to reduce inflammation in the lungs.
One of the more promising new types of medications that may be particularly helpful for this condition are immunomodulators. They work to alter the immune system’s response to asthma triggers . At present the only immunomodulator approved by the FDA is Xolair (omalizumab).
The best advice here is to avoid your known allergen triggers as effectively as possible. For pollen, it’s wise to stay indoors when pollen counts are high in your area and to make sure the filter in your air conditioner is clean if you’re using one. HEPA air filters are best. Also, don’t use an evaporative cooler.
If dust or dust mites are your trigger, then you need to be very proactive in dusting surfaces in your home, and having rooms that don’t have wall-to-wall carpet is preferable too. Wash sheets and bedding once a week, and use allergen-proof covers on them if you can.
Controlling indoor humidity is helpful for people with this condition. A dehumidifier or air conditioner should be used if moisture is above 40% in your home.